williams



March 17, 1964 J. R. WILLIAMS FURNACE Filed Feb. 23, 1962 FIG.-

INVENTOR. JOHN R. WILLIAMS BY ATTORNEY.

United States Patent 3,125,327 FURNACE John Roger Williams, Ambler, Pa., assignor to Salas Corporation of America, Dresher, Pa., a corporation of Pennsylvania Filed Feb. 23, 1962, Ser. No. 175,147 Claims. (Cl. 263-15) The present invention relates to furnaces, and more particularly to a barrel type furnace in which elongated work pieces, such as steel tubes and rods, can be heated to hot working temperature in a scale-free condition.

In the heating of steel of various types to hot working temperature, there is usually formed on the surface thereof a scale that must be removed prior to the time the hot working is performed. This scale is objectionable both because it represents a substantial loss of metal in an expensive form, as well as because of the extra operations that are required to remove the scale from the surface of the steel before it can be worked.

It is an object of the invention to provide a furnace in which steel can be heated in an atmosphere which will prevent scaling from taking place.

It is a further object of the invention to provide a furnace in which primary and secondary combustion take place; the primary combustion being of a rich fuel-air mixture and taking place in a chamber closely surrounding the work, and the secondary combustion burning the fuel not used in the primary combustion and additional fuel and taking place in a chamber surrounding the first chamber. V V

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objects attained with its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a side view partly in section of a furnace on line 1-1 of FIG. 2, and

'FIG. 2 is a section taken on line 2--2 of FIG. 1.

Referring to the drawing, there is shown a furnace unit that can be used separately, but is primarily intended to be a unit of a barrel furnace line, such as is shown in Hess Patent No. 2,529,690. In a furnace line of this type, the furnace units are identical, and work is moved from one to the other by conveyor rolls that are located between the units. In this case, the furnace includes end walls 1 which have supporting legs on them, and which support an outer furnace wall 2 that forms a substantially cylindrical furnace chamber 3. Extending upwardly from the bottom of the wall are posts 4 which support an inner cylindrical wall 5 forming an inner substantially cylindrical furnace chamber 6 which is concentric with chamber 3. Each of the posts is provided with a vertical passage 7, the lower end of which is closed by a plug 8 that can be removed in order to remove any dirt which may accumulate therein. The posts are also provided with a side passage 9, the lower end of which receives an excess gas burner 11 that is supplied with fuel and air through a pipe 12. The inner wall 5 is provided with a plurality of radially extending openings 13 which are located around and along the wall to provide communication between chambers 3 and 6. The furnace walls and the posts may be formed of separate pieces that are assembled, or they may be formed of cast refractory material. In either event, those materials used to form the various walls and posts will be of the type that is generally used in relatively high temperature furnaces, with the outer refractory being protected by a metal cover, as shown in the drawing, in accordance with ordinary furnace practice.

Outer Wall 2 has built into it a series of radiant cup type burner blocks 14, each of which is provided with a cup-shaped depression 15. Fuel and air are distributed to be burned along the surface of the cup by means of a distributor 16 extending through the block and the furnace wall. The back of the furnace is provided with an air chamber 17 to which air is supplied by means of a pipe 18. There is also provided a gas supply pipe 19. It is preferred that these burners be of the type that is shown in Furczyk Patent No. 2,855,033. Outer chamber 3 is provided with a vent 21, through which products of combustion may be exhausted.

In the operation of the furnace, work in the form of a rod or tube, for example, is introduced into the furnace through an axial opening 22. If the work is to be heated on a continuous basis, as is usual and as disclosed in the above mentioned Hess patent, similar axially disposed openings will be provided in each of the end walls. Burners 11 are supplied with a fuel and air mixture that has an excess amount of fuel up to approximately 50%. Ordinarily, a mixture of this type, if it will burn at all, will only burn with a relatively low temperature. Such a mixture, however, has the characteristic of providing a protective atmosphere around the work, so that scaling of the work will not take place. Burner 11 is so positioned in post 4 that the fuel mixture enters chamber 6 substantially tangentially, and will move around the chamber to encircle the work completely and thereby protect it. The products of combustion produced by the burning of this rich mixture contain a large percentage of unburned fuel. These gases will be discharged from chamber 6 through openings 13 into the outer concentric chamber 3. It is intended that the fuel and air supplied to the radiant burners 14 will be in such proportions that there is enough excess air in this mixture to combine With and burn the unburned fuel discharged into chamber 3. The combustion which takes place in chamber 3 takes place with a substantially stoichiometric mixture of fuel and air, so that the heat is intense. This heat will heat wall 5 to incandescence so that this wall will radiate heat toward the work. The heat of this wall will also be sufiicient to raise the temperature of the rich mixture of gas supplied to chamber 3, so that this fuel mixture Will burn at a high enough temperature to supply additional heat to the work.

The result of the furnace arrangement and the method of operating it is that the work is completely protected while it is in the furnace with an atmosphere produced by primary combustion, which will prevent the formation of any scale on the work surface. The secondary combustion produced in chamber 3 uses the unburned fuel from chamber '5 so that the efficiency of the furnace is high, and at the same time suflicient heat is supplied to the work to heat it to temperatures well above those required for the hot working of steel, for example.

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed Without departing from the spirit and scope of the invention set forth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

What is claimed is:

1. In a furnace, the combination of a first cylindrical wall forming an inner chamber, a second cylindrical wall forming an outer chamber, means to mount said first wall concentrically within said second wall to form a pair of inner and outer concentric chambers, a pair of end plates to close the ends of said chambers, at least one of said end plates having an opening concentric with said inner chamber through which work to be heated can be inserted, said means to mount being provided with a passage terminating in said inner chamber, a burner in said passage directed toward said inner chamber, burners in said second wall directed toward said first wall, means forming passages in said first Wall for combustion products to flow from said inner chamber to said outer chamber, and means forming an exhaust stack from said outer chamber.

2. A furnace for heating elongated objects comprising structure forming a pair of substantially concentric and cylindrical furnace chambers having a wall between them and a post locating the inner chamber in the outer one, means forming axially aligned openings axially located in said inner chamber through which work to be heated can travel, burners operative to burn a rich mixture of fuel and air mounted in said post to discharge products of combustion from said burners into the inner chamber, said wall being provided with a plurality of openings through which products of combustion can travel from the inner to the outer chamber, and a plurality of burners adapted to burn a lean mixture of fuel and air mounted in said structure to fire into the outer chamber.

3. In a furnace, a pair of end walls having axially aligned openings therein, a first Wall forming an inner substantially cylindrical chamber between said end walls with said openings axial of the chamber, said first wall being provided along its length with a plurality of openings, said first wall being provided with supports having passageways extending into said chamber, burners in said supports directed toward said passages, said burners directing gases through said passages substantially tangentially toward said inner chamber, a second wall encircling said first wall and supports and connected to the ends of the supports to form an outer substantially cylindrical chamber surrounding said inner chamber, radiant cup type burners in said second Wall directed to- 4- ward said first wall, and means forming a vent for exhaust gases in said outer chamber.

4. In a furnace, structure forming the wall and ends of an inner substantially cylindrical furnace chamber, structure forming the wall and ends of an outer substantially cylindrical furnace chamber surrounding said inner chamber, means forming a plurality of openings in the wall of said inner chamber and through which said inner chamber communicates with said outer chamber, means to support said first chamber in said second chamber, burners in said support means operative to direct a rich mixture of fuel and air into said inner chamber, burners in the wall of said outer chamber. operative to supply a lean mixture of fuel and air to said outer chamher, and means forming an opening in at least one end of said inner chamber through which work to be heated can be inserted into said inner chamber.

5. In a furnace, structure forming an outer substantially cylindrical and horizontally disposed furnace chamber having a wall and two ends, at least one of said ends being provided with an axial opening, a post extending upwardly in said chamber from said wall, a second cylindrical wall forming an inner chamber supported by said post and coaxial with said opening, said second wall being provided with a plurality of openings therein, said post being provided with a passage therein to the interior of said inner chamber, a burner in said passage directed to supply gases substantially tangentially toward said inner chamber, and a plurality of burners in said first mentioned wall directed toward said outer chamber.

References Cited in the file of this patent UNITED STATES PATENTS 2,638,333 Hess May 12, 1953 2,763,476 Ness et al. Sept. 18, 1956 2,799,491 Rusciano July 16, 1957 2,845,260 Rusciano July 29, 1958 2,988,350 Munford June 13, 1961 3,022,057 Schmidt et al. Feb. 20, 1962 

1. IN A FURNACE, THE COMBINATION OF A FIRST CYLINDRICAL WALL FORMING AN INNER CHAMBER, A SECOND CYLINDRICAL WALL FORMING AN OUTER CHAMBER, MEANS TO MOUNT SAID FIRST WALL CONCENTRICALLY WITHIN SAID SECOND WALL TO FORM A PAIR OF INNER AND OUTER CONCENTRIC CHAMBERS, A PAIR OF END PLATES TO CLOSE THE ENDS OF SAID CHAMBERS, AT LEAST ONE OF SAID END PLATES HAVING AN OPENING CONCENTRIC WITH SAID INNER CHAMBER THROUGH WHICH WORK TO BE HEATED CAN BE INSERTED, SAID MEANS TO MOUNT BEING PROVIDED WITH A PASSAGE TERMINATING IN SAID INNER CHAMBER, A BURNER IN SAID PASSAGE DIRECTED TOWARD SAID INNER CHAMBER, BURNERS IN SAID SECOND WALL DIRECTED TOWARD SAID FIRST WALL, MEANS FORMING PASSAGES IN SAID FIRST WALL FOR COMBUSTION PRODUCTS TO FLOW FROM SAID INNER CHAMBER TO SAID OUTER CHAMBER, AND MEANS FORMING AN EXHAUST STACK FROM SAID OUTER CHAMBER. 